STOP Early Journal Content on JSTOR, Free to Anyone in the World This article is one of nearly 500,000 scholarly works digitized and made freely available to everyone in the world by JSTOR. Known as the Early Journal Content, this set of works include research articles, news, letters, and other writings published in more than 200 of the oldest leading academic journals. The works date from the mid-seventeenth to the early twentieth centuries. We encourage people to read and share the Early Journal Content openly and to tell others that this resource exists. People may post this content online or redistribute in any way for non-commercial purposes. Read more about Early Journal Content at http://about.jstor.org/participate-jstor/individuals/early- journal-content . JSTOR is a digital library of academic journals, books, and primary source objects. JSTOR helps people discover, use, and build upon a wide range of content through a powerful research and teaching platform, and preserves this content for future generations. JSTOR is part of ITHAKA, a not-for-profit organization that also includes Ithaka S+R and Portico. For more information about JSTOR, please contact firstname.lastname@example.org. THE CONDOR A Bi-MontHly Magazine of Western OrnitHology Volume XXII November-December. 1920 Number 6 [Issued December 4, 1920] THE WING CLAW IN SWIFTS By ALEXANDER WETMORE IN a paper on "The Claws and Spurs on Birds' Wings", Jeffries (Proc. Boston Soc. Nat. Hist., xxi, 1881, pp. 301-306) recorded in a tabular survey of the occurrence of wing claws in birds that the wing claw was present in the Old World swifts of the genus Micropus and that no wing claw was found in the Chimney Swift (Chaetura pelagica). A brief examination of a series of Chimney Swifts showed the present writer that this species possessed well developed wing claws so that what had appeared to be another character separating the two subfamilies of spiny-tailed and soft-tailed swifts proved invalid. Opportunity was taken in this connec- tion to examine for this character all of the species of swifts available in the collections of the United States National Museum with results that proved of some interest. In all, 48 species belonging to 12 genera were available, as in- dicated in the following list. In arranging my notes on these swifts I have encountered difficulty in the arrangement, treatment and choice of names to be used; for there have been varying opinions as to the limits of groups and the allocation of subspecies, while no recent comprehensive monograph has covered the entire family in a manner wholly satisfactory. In general the arrangement of the genera is that given by Mr. Ridgway (Bull. 50, U. S. Nat. Mus., v, 1911, pp. 685-686), with the inclusion of Tachynautes (Oberholser, Proc. U. S. Nat. Mus., xxvm, 1905, p. 860), while the majority of the species are taken as they stand in Sharpe's Hand-List (vol. n, 1900, pp. 89-96). The genus Collocalia is based on Oberhol- ser 's monograph of this group (Proc. Acad. Nat. Sci. Phila., vol. 58, 1906, pp. 177-212), save that the treatment of Collocalia fuciphaga, C. vestita, and C. lovi is that of Streseman (Verh. Orn. Ges. Bayern, Bd. xn, 1914, pp. 1-12). New species and subspecies not covered by these authors are included in what appears to be their logical positions. The writer does not venture to say that 198 THE CONDOR Vol. XXII the combination produced is a happy one, but believes that it will at least en- able others to determine what birds he has seen. Micropus melba (Linnseus) Micropus aequatorialis (Muller) Micropus apus (Linnseus) Micropus pacificus (Latham) Micropus horus (Heuglin) Micropus af finis (J. E. Gray) Micropus subfurcatus (Blyth) Micropus andicola (Lafresnaye and D'Orbigny) Micropus myoptilus (Salvadori) Aeronautes melanoleucus (Baird) Panyptila sanctihieronymi Salvin Panyptila cayanensis (Gmelin) Tachynautes parvus (Lichtenstein) Tachornis infumntus (Sclater) Tachornis phoenicobius Gosse Hirundapus celebensis (Sclater) Hirundapus caudacutus (Latham) Hirundapus giganteus (Temminck) Mearnsia picina (Tweeddale) Streptoprocne zonaris (Shaw) Streptoprocne semicollaris (Saussure) Nephoecetes niger (Gmelin) Cypseloides brunneitorques (Lafres- naye) Cypseloides cherriei Ridgway Chaetura pelagica (Linnaeus) Chaetura vauxi (Townsend) Chaetura richmondi Ridgway Chaetura gaumeri Lawrence Chaetura acuta (Gmelin) Chaetura poliura (Temminck) Chaetura cinereiventris Sclater Chaetura stictilaema (Reichenow) Chaetura leucopygialis (Blyth) Collocalia innominata Hume Collocalia ocisia Oberholser Collocalia fuciphaga fuciphaga (Thunberg) Collocalia fuciphaga vanikorensis (Quoy and Gaimard) Collocalia fuciphaga amelis Oberhol- ser Collocalia fuciphaga unicolor (Jer- don) Collocalia vestita vestita (Lesson) Collocalia vestita mearnsi Oberholser Collocalia vestita elaphra Oberholser Collocalia vestita aenigma Riley Collocalia origenis Oberholser Collocalia lowi lowi (Sharpe) Collocalia lowi palawanensis Strese- man Collocalia inopina Thayer and Bangs Collocalia thespesia Oberholser Collocalia francica townsendi Ober- holser Collocalia francica inexpectata Hume Collocalia francica germani Oustalet Collocalia troglodytes G. R. Gray Collocalia marginata Salvadori Collocalia linchi affinis Beavan Collocalia linchi elachyptera Oberhol- ser Collocalia linchi isonota Oberholser Collocalia linchi oberholseri Strese- man Collocalia dodgei Richmond Collocalia esculenta (Linnaeus) Collocalia bartschi Mearns The wing claw in the Micropodidae is placed near the tip of the thumb or pollex and is concealed beneath the feathers that form a sharp anterior margin on the wing at that point. The large series of birds studied were examined under a binocular dissecting microscope with a magnification of eight diame- ters. The use of this instrument left both hands free to manipulate the bird, a necessary arrangement, as the claw is small and at times difficult to locate among the feathers. The claw in general is blackish or dusky in color, and is comparatively long, with the tip recurved in a slight hook. It is attached rather loosely and may be removed easily, but where a claw has been broken away, its former location is plainly indicated by a scar. The form of the claw varies to some extent, and in abnormal individuals it may degenerate into a short knob with slight projection. In all of the swifts examined wing claws were normally developed save in one group of species belonging to the genus Collocalia. In the various subspe- cies of C. linchi the wing claw was normal in some cases, rudimentary in oth- ers, and occasionally was absent on one or both wings. The same was true in a Nov., 1920 THE WING CLAW IN SWIFTS 199 series of nine C. esculenta. The wing claw was much reduced in seven C. troglodytes and in one specimen was absent on one wing. In Collocalia mar- ginata no trace of a wing claw was found in an examination of both wings of nine individuals, and wing claws were absent also in the type of C. dodgei (the only specimen of this species seen). Wing claws were present in the type spe- cimen of C. bartschi. In the other species of Collocalia available (C. innominata, ocista, fuciphaga, vestita, origenis, lowi, inopina, thespesia, and francica) wing claws were present on both wings, though occasionally they were small and often were curled and twisted. In one individual of C. f. amelis the wing claw on the right wing grew from the base of the pollex instead of the tip. The wing claw may possibly develop rather late in the growth of the young bird, as I found it absent entirely in three nestlings of Collocalia I. isonota, but pres- ent in both wings in a fully fledged young of Collocalia origenis. It is inter- esting to note that in the Tree Swifts (Hemiprocnidae), a family considered to be closely allied to the true swifts (Micropodidae), no wing claw is present. The species examined include Hemiprocne longipennis, mystacea, comata, wal- lacei and perlonga. While it has proved that the wing claw in the Micropodidae is not a char- acter of taxonomic value it has been interesting to note its persistence in gen- eral and its absence in certain cases. The section of edible nest swiftlets, cover- ing the small blue-black species with more or less white in the plumage, seems to be on the way to discarding the wing claw, though here the loss is not as yet universal and may vary in one species- or even in one individual. From the present evidence I am inclined to consider the wing claw in swifts as an archaic trait that is no longer of value and is on the way to being lost. There is no evidence at hand to show that the claw is used by these birds in attaching or climbing on the rough surfaces on which they rest. No wear is evident on the wing claw itself, nor is there abrasion on the feathers concealing it. From a limited amount of material (all in dried skins) it seems that the wing claw does not appear until the young bird is well feathered, so that it is not of use in a juvenile stage. This, however, should be carefully verified in fresh material for, if this claw be considered an archaic character, it is strange if it does not appear very early in the life of the individual. Biological Survey, Washington, D. C, May 26, 1920.